Omni-directional towbarless aircraft transporter for moving aircraft

ABSTRACT

An apparatus for moving parked aircraft with an omni-directional tractor via an aircraft lift dolly that is revolvably coupled thereto. The aircraft lift dolly may be removably coupled to the omni-directional tractor or may be integral to it. The aircraft lift dolly includes a lift mechanism having a lift carriage which is selectively elevated. The lift carriage includes a fixed forward chock and a rear chock that moves longitudinally and laterally with respect to the forward chock. The chocks are positioned about the aircraft nose gear without movement of the aircraft. Elevating the lift cradle elevates the chocks and the nose gear cradled therebetween.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon provisional application 60/851,866 filedon Oct. 13, 2006, the priority of which is claimed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to a wheeled vehicle designed to moveparked aircraft. In particular, the invention relates to towbarlessaircraft transport vehicles that move aircraft by lifting the noselanding gear clear of the ground to move the aircraft without the use ofconnected tow bars.

2. Description of the Prior Art

Aircraft transport tractors commonly employ an attached towbar that isused to engage nose gear of aircraft to push or pull the aircraft. Theaircraft landing gear remain on the ground at all times during transportby a conventional towbar-type aircraft transport tractor. However,towbarless aircraft transport vehicles, which lift aircraft nose gear upoff of the ground, are also in use. Towbarless tractors are designed toeliminate all but one pivot point to reduce turn limit damage, eliminatejackknifing, and provide increased maneuverability.

FIG. 1 shows a typical towbarless aircraft transport tractor (1) ofprior art. The tractor (1) utilizes a scoop or bucket (2) that lays flaton the ground and receives the aircraft landing nose gear wheels. Aharness (3) is secured to the aircraft, and the aircraft is pulled intothe bucket by a winch located on the tractor. Once the aircraft iswinched into the bucket tightly against the bucket wall (4), the bucketis raised and tilted rearward, securing the aircraft and making itpossible to tow. As a result of the tilting of the bucket, the geometryof the landing gear may have a forward rake angle, which may place thenose gear in a bind when the aircraft, and hence the nose gear, areturned sharply.

Other lift designs may be used to lift aircraft nose gear for transport.For instance, a scoop or receiver bucket may be placed in front of theaircraft wheels and a set of arms with either powered wheels or freewheeling wheels are placed behind the landing gear wheels. The rearwardplaced rollers are then pulled forward forcing the aircraft wheels toroll forward into the receiver portion of the device. When the aircraftis secured against the front portion of the receiver, the landing gearwheels are raised and can be transported. Other devices may employwinching devices that winch the aircraft landing gear forward onto alazy susan turntable. The swiveling turntable allows the tractor tomaneuver the aircraft with less steering of the aircraft nose landinggear, and thus less risk of binding the nose gear.

Towbarless aircraft transport tractors of prior art (1) all require thatthe aircraft be moved from its original position to be captured in thelifting bucket, for example by being winched forward by a harness.Because other equipment may be attached to the aircraft during aircraftservicing, the process of capturing the aircraft into the bucket mayneed to be deferred until the aircraft is completely free to be moved,thus minimizing the amount of preparation and pre-staging of thetransport tractor that may be accomplished and increasing overalltransport time. It is therefore desirable to have an aircraft liftmechanism that does not require the aircraft to be moved during thecradling process.

Furthermore, the harness must be manually attached to and released fromthe aircraft as part of the transport process, which increases transporttime and effort. Therefore, it is desirable to have an aircraft liftmechanism that allows an operator to completely cradle and release theaircraft nose gear from the operators seat of the aircraft transporttractor.

Towbarless aircraft transport tractors (1) of prior art are typicallyfour-wheeled vehicles with fixed drive wheels (5) located at the liftingend of the tractor and steerable wheels (6) located at the opposite end.The fixed wheels (5) are powered and provide tractive force for thetractor (1) and towed aircraft. The weight of the aircraft actsdownwardly close to the drive wheels and helps to provide traction.

The two steerable wheels (6) simultaneously pivot within a limitedangular range. Because there is a fixed distance between the fixed wheelaxle and the steerable wheel axle, a turning radius exists that farexceeds the space actually occupied by the vehicle itself. The longerthe distance between axles, the larger the turning radius that isrequired to change directions of the vehicle. A large turning radiusmakes maneuvering around tight areas difficult and often dangerous. Inan area where movement is constrained, a vehicle with a small turnradius is advantageous. Any increase in maneuvering efficiency andsafety generally amounts to significant cost savings. It is desirable,therefore, to have a vehicle with greater maneuverability to enhance thesafety of the operator, the aircraft, and the surrounding environment.

Furthermore, towbarless aircraft transport tractors (1) of prior art aresingle-use specialized vehicles characterized by an integral aircraftlift mechanism. As tractors are used in a number of aircraft servicingoperations, such as for towing baggage carts or moving aircraft withconventional towbars, it is advantageous to use a common tractor designthat can perform numerous services. Interoperability of tractors reducescapital costs, improves redundancy, and provides operationalflexibility. Therefore, it is desirable to incorporate an aircraft liftmechanism in a dolly that can be removably coupled with a multi-purposetractor.

3. Identification of Objects of the Invention

A primary object of the invention is to provide a towbarless aircrafttransport vehicle that maneuvers an aircraft with the utmost precision,making it possible to place the aircraft in congested ramps and hangerswith less space required for maneuvering.

Another object of the invention is to provide a towbarless aircrafttransport vehicle that reduces the labor required to operate the vehicleand connect to aircraft.

Another object of the invention is to provide a towbarless aircrafttransport vehicle that reduces the possibility of injury to personneland aircraft while towing aircraft.

Another object of the invention is to provide a towbarless aircrafttransport vehicle that reduces the stresses placed on the aircraftlanding gear, for example by loading the nose gear in the direction oftravel during transport.

Another object of the invention is to provide a towbarless aircrafttransport vehicle that captures the aircraft for transport withoutmoving the aircraft from its original position over the ground, with theonly movement being lifting the nose gear straight up prior to movement.

Another object of the invention is to provide a tractor attachment thatis capable of performing lifted aircraft towing and handling and whichcan be easily decoupled from the tractor, allowing the basic tractor tobe used for other purposes such as using a conventional tow bar,powering a sweeper, or moving snow with a snow plow attachment.

SUMMARY OF THE INVENTION

In a first embodiment of the invention, one or more of the objectsdescribed hereinbefore and other advantages and features of theinvention are incorporated in a aircraft transport vehicle consistingessentially of an omni-directional tractor having an accessory aircraftlift and transport dolly tool revolvably connected thereto. Theomni-directional tractor provides superior maneuvering capability andthe towbarless aircraft lift dolly minimizes stresses imparted to thetowed aircraft nose gear.

In one variation, the omni-directional tractor is removably coupled tothe aircraft lift dolly, allowing the omni-directional tractor to beused with other accessory tools, such as with baggage carts,conventional towbars, sweepers, or snow plows. In another variation, theomni-directional tractor and aircraft lift dolly are integral, forming aspecialized aircraft transport vehicle.

The aircraft lift dolly may include a handling mechanism that lowershandling wheels to lift the rear dolly wheels up off the ground. Thehandling wheels are oriented perpendicular to the dolly longitudinalaxis. By pinning the lift dolly to the omni-directional tractor so thatno rotation occurs therebetween, the entire transport vehicle can bemade to move transversely to the dolly longitudinal axis or to rotateabout the omni-directional tractor vertical axis.

In a second embodiment of the invention, one or more of the objectsdescribed hereinbefore and other advantages and features of theinvention are incorporated in vehicle in which the aircraft lift dollyis combined with either an omni-directional tractor or a conventionalfour-wheeled tractor. In one variation, the aircraft lift dolly isremovably coupled to the tractor, and in another variation, the aircraftlift dolly is integral with the tractor. The aircraft lift dollyincludes a lift mechanism that cradles the aircraft without requiringthe aircraft to be moved over the ground.

The aircraft lift mechanism includes a lift carriage and forward chockthat can be selectively raised with respect to the transport vehicle.The lift carriage carries a rear chock, which can be movedlongitudinally and laterally with respect to the forward chock. Inoperation, the aircraft transport vehicle is driven to the liftingposition where the front aircraft nose gear abuts the forward chock. Therear chock is then moved to abut the rear of the nose gear. The liftcarriage is elevated, raising the forward and rear chocks and the nosegear cradled therebetween. Thus, the aircraft can be cradled and liftedwithout moving the aircraft on to a lift bucket.

The aircraft lift dolly may include a handling mechanism that lifts theforward end of the dolly from the ground to facilitate coupling oruncoupling the dolly from the tractor. The aircraft lift dolly may alsotelescopically extend along its longitudinal axis to provide greaterflexibility in handling aircraft.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in detail hereinafter on the basis of theembodiments represented in the accompanying figures, in which:

FIG. 1 is an isometric perspective view of a towbarless aircrafttransport tractor of prior art showing a conventional four-wheeledtractor equipped with a bucket for receiving and lifting the nose gearof an aircraft and a harness for winching the aircraft nose gear on tothe bucket;

FIG. 1A is a plan view of a prior art omni-directional tractor oromni-directional vehicle (ODV).

FIG. 2 is a plan view of an aircraft transport vehicle according to apreferred embodiment of the invention showing an omni-directionaltractor and an aircraft lift dolly that is removably and revolvablyconnectable to the tractor;

FIG. 3 is a left side elevation view of the aircraft transport vehicleof FIG. 2;

FIG. 4 is a left side elevation detailed view of a hitch assembly forcoupling the aircraft lift dolly to the omni-directional tractor;

FIG. 5 is a detailed front elevation view of the aircraft lift dolly ofFIGS. 2 and 3 taken along lines 5-5 of FIG. 2 showing a dolly handlingmechanism, in both the engaged and disengaged positions, for elevatingthe aircraft lift dolly;

FIG. 6 is a plan view of the aircraft transport vehicle of FIG. 2 shownwith the omni-directional tractor coupled to the aircraft lift dolly tocreate a single, harmonious aircraft transport system;

FIG. 7 is a left side elevation view of the coupled aircraft transportvehicle of FIG. 6;

FIG. 8 is an isometric perspective view of the coupled aircrafttransport vehicle of FIG. 6,

FIG. 9 is a plan view of the coupled aircraft transport vehicle of FIG.6 shown with the omni-directional tractor oriented perpendicular to thelongitudinal axis of the vehicle and with dolly handing wheels deployedso that the entire vehicle can be moved transversely or rotated aboutthe omni-directional tractor vertical axis;

FIG. 10 is a left side elevation view of the coupled aircraft transportvehicle of FIG. 9 showing dolly handing wheels deployed to lift the rearend of the aircraft lift dolly and the dolly wheels clear of the ground;

FIG. 11 is a plan view of the coupled aircraft transport vehicle of FIG.6 shown with the omni-directional tractor rotated counterclockwise andthe aircraft lift dolly in a telescopically extended configuration toaccommodate aircraft of varying sizes;

FIG. 12 is a plan view of an aircraft transport vehicle according to analternative embodiment of the invention showing an omni-directionaltractor revolvably and permanently connected to an aircraft left dollyto form a special purpose ground support vehicle;

FIG. 13 is a detailed plan view of the aircraft lift mechanism of FIG. 2according to a preferred embodiment of the invention showing a liftcarriage with forward chock and laterally moving support arms carryinglongitudinally moving left and right rear chocks;

FIG. 14 is a cross section view of the aircraft lift mechanism takenalong lines 14-14 of FIG. 13 showing the aircraft transport vehicle andlift mechanism moving toward an aircraft nose gear for receiving andcradling thereof;

FIG. 15 is a detailed plan view of the aircraft lift mechanism of FIG.13 showing left and right support arms moving laterally toward theaircraft nose gear;

FIG. 16 is a detailed plan view of the aircraft lift mechanism of FIG.15 showing left and right rear chocks moving longitudinally forwardtoward the aircraft nose gear;

FIG. 17 is a cross section view of the aircraft lift mechanism takenalong lines 17-17 of FIG. 16 showing left and right rear chocks movinglongitudinally forward toward the aircraft nose gear;

FIG. 18 is a detailed plan view of the aircraft lift mechanism of FIG.16 showing cradled aircraft nose gear ready for lifting by the liftcarriage;

FIG. 19 is a cross section view of the aircraft lift mechanism takenalong lines 19-19 of FIG. 18 showing upward movement of the liftcarriage and aircraft nose gear; and

FIG. 20 is the aircraft lift mechanism of FIG. 19 showing a cradled andlifted aircraft nose gear.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

In describing aircraft transport vehicles herein, a convention isadopted that when referring to the aircraft lift dolly 100, the terms“forward” or “front” refer to that portion of the dolly 100 that facesthe same direction as the aircraft's compass heading when the aircraftis carried by the vehicle 10, and left and right designations match theaircraft's left and right sides, respectively, regardless of thedirection of travel, the direction the operator is facing, or theorientation of the omni-directional tractor 8. However, when referringto the omni-directional tractor 8, left, right, front and backreferences match that of the operator's left, right, front and back,respectively.

Referring to FIGS. 2-3, according to a preferred embodiment of theinvention, the aircraft transport vehicle 10 includes anomni-directional vehicle (ODV) 8 that is revolvably coupled to a dolly100 equipped with an aircraft lift assembly 200 for elevating the nosegear of an aircraft. U.S. Pat. No. 6,581,703, issued to Hammonds andentitled “Omni Direction Vehicle” teaches one how to make and use an ODVhaving a circular perimeter and a zero turn radius; it is incorporatedherein in its entirety by reference.

ODV 8 preferably includes a circular frame 14, about which dolly 100 isrevolvably mountable. As shown by hidden lines in FIG. 2, ODV 8 includesa power source 22 mounted to the frame 14 and first and second drivewheels 12L, 12R rotatively coupled to the frame 14, and one or moreswivel casters carried at the underside of frame 14 to support ODV 8 onthe ground and prevent it from toppling. Preferably, four swivel casters63R, 63L, 64R, 64L are used, as discussed in detail hereinafter. Anoperator seat 50 is coupled to frame 14 near the center of the ODV 8.

The drive wheels 12L, 12R are disposed along and rotate about ahorizontal axis 18. When drive wheels 12L, 12R are rotated in oppositedirections at the same speed, they revolve 360 around a vertical axis16. Drive wheels 12L, 12R are independently driven by first and secondmotors 26L, 26R, which are powered by power source 22. Power source 22may be a battery or an internal combustion engine and hydraulic pump,for example, and motors 26L, 26R may be electric or hydraulic motors.First and second control levers 31L, 31R, located on either side ofoperators seat 50, are operatively coupled to and control the speed anddirection of the first and second drive wheels 12L, 12R, respectively.

In a preferred embodiment of the invention, ODV 8 includes dual forwardswivel casters 63R, 63L, which are mounted on articulated linkages thatare supported by dual air bags. Under normal operating, casters 63R, 63Ldo not support any of the weight of tractor 8 and are mounted in aposition just clear of the ground. When the forward-moving vehiclesuddenly stops or turns, the air suspension of front casters 63R, 63Lstabilizes the tractor 8 much like an automobile suspension, absorbingenergy caused by the weight of the tractor shifting forward. The airbags are adjustable in stiffness by a control located in the tractorinstrument panel and can be set as stiff or soft, depending on thesmoothness of the surface on which ODV 8 is operating.

ODV 8 is weighted so that the center of gravity is located behind thedrive wheel horizontal axis 18. ODV 8 preferably includes dual rearcasters 64R, 64L, which support the rear-heavy ODV 8 and keep it fromtoppling over when operating independently of dolly 100. Unlike forwardcasters 63R, 63L, rear casters 64R, 64L are preferably not mounted on anair suspension.

Aircraft dolly 100 includes a frame 101 having a forward end 102 thatrevolvably mounts to ODV 8 and a rear end 104 that carries an aircraftlift mechanism 200 that is designed and arranged to lift the nose gearof an aircraft having tricycle-style landing gear. Dolly 100 preferablyincludes wheels 110R, 110L located near the rear end 104 of dolly 100 tosupport the weight of the carried aircraft. Ideally, wheels 110R, 110Lcarry approximately sixty percent of the loaded dolly weight, with ODV 8carrying the remaining forty percent.

Preferably, storage batteries, an independent hydraulic power unit andsolenoid controls are located inside compartments (not illustrated)formed within the body of dolly 100, thus obviating the need fortransferring power from ODV 8 to dolly 100. Switches for controlling thefunctions of all hydraulic powered components of aircraft lift mechanismare located in an operators console 112 located at forward end 102within easy reach of the operator, making it possible to operate dolly100 entirely from ODV seat 50 and thus requiring less labor forattachment and detachment of aircraft. Preferably, console 112 is offsetto one side of the longitudinal centerline 105 of aircraft transporttractor 10 so as not to obstruct an operator's view of the aircraft nosegear during transport.

According to one embodiment of the invention, the aircraft liftmechanism may be any suitable lift mechanism, including prior art liftmechanisms such as those described hereinbefore which require that theaircraft be winched or pulled on to a bucket or cradle. The combinationof ODV 8 with a prior art aircraft lift mechanism provides increasedmaneuverability over a conventional four-wheeled tractor carrying thesame lift mechanism. It is preferred, however, that a lift mechanism200, as described hereinafter with reference to FIGS. 13-20, be usedwith dolly 100 and/or ODV 8.

Referring to a preferred embodiment of FIGS. 2-3, ODV 8 is equipped witha circumferential revolvable appendage ring 9, which surrounds ODVcircular frame 14. The inner diameter of appendage ring 9 is defined bya bearing race 38. The bearing race may be integral to appendage ring 9or may be a separate member that is rigidly attached to the inside ofappendage ring 9. The bearing race 38 provides smooth surfaces forreceiving and revolvably coupling ODV 8, which preferably has aplurality of vertical and horizontal rollers 44, 46, 47 that engage androtatably capture bearing race 38 in both vertical and horizontaldirections with substantially no looseness. The mounting positions ofthe rollers generally match the curvature of the bearing race 38, thusallowing the bearing race 38 (and attached appendage ring 9) to rotatesmoothly with minimal friction and resistance about the ODV 8.Preferably, the rollers are evenly circumintervaled, orcircuminterspersed, about the perimeter of the ODV 8, but the number,size, and placement of the rollers may vary depending on the designloads. The revolvable coupling assembly, including rollers 44, 46, 47and bearing race 38, should preferably be completely circumferential tohelp evenly distribute loads and minimize point-loading-inducedstresses, friction, and coupling failures. The rollers may be equippedwith ball bearings to provide smooth rotation under load. Alternatively,other circumferential coupling arrangements may be used to revolvablycouple appendage ring 9 to ODV 8. For instance, a bearing race may berigidly attached to the ODV frame 14 and the engaging rollers may beintervaled within and attached to the appendage ring 9. U.S. patentapplication Ser. No. 11/363,979 filed on Feb. 28, 2006 in the name ofHammonds and entitled “Omni-Directional Vehicle with FullCircumferential Revolvable Hitch” teaches one how to make and use an ODVwith a revolvable appendage ring; it is incorporated herein by referencein its entirety.

Appendage ring 9 serves as a point of attachment for aircraft lift dolly100. Two hitches 70R, 70L, located 180 degrees from each other aboutappendage ring 9, are preferably used to selectively and quickly coupleand uncouple aircraft lift dolly 100 to ODV 8. FIG. 4 shows detail ofleft hitch 70L of FIGS. 2 and 3. Referring to FIGS. 2-4, each hitch 70R,70L preferably includes a ball 72R, 72L mounted to appendage ring 9; acomplimentary socket 74R, 74L, mounted on a tang 76R, 76L on the forwardend 102 of aircraft lift dolly 100, connects to ball 72R, 72L. To coupledolly 100 to appendage ring 9, the forward end 102 of dolly 100 isinitially elevated so that sockets 74R, 74L are higher than balls 72R,72L. ODV 8 is driven into a circular profile 106 in the forward end 102of dolly 100, with appendage ring 9 oriented so that the balls 72R, 72Lare located directly below sockets 74R, 74L. The forward end 102 ofdolly 100 is then lowered, so that sockets 74R, 74L receive balls 72R,72L and are locked thereto in a manner similar to that of an ordinaryboat trailer, for example. Hitch arrangements other than ball and socketmay also be used as appropriate. The hitch arrangement of FIGS. 2-4provides a full gimbal mount that allows free rotation of dolly 100 withrespect to ODV 8 while simultaneously allowing independent verticalpivoting of ODV 8 and dolly 100 for negotiating uneven ground surfaces.

FIG. 5 shows a dolly handling assembly 118 that is used to lift thefront end 102 of dolly 100 from the ground, making it possible toelevate sockets 74R, 74L to simplify connection to and disconnectionfrom the omni-directional tractor 8. In a preferred embodiment, handlingassembly includes left and right handling wheels 120L, 120R that arerotatively connected to distal ends of left and right bell cranks 122L,122R. Bell cranks 122L, 122R are pivotally connected at their medialends 123L, 123R to the frame 101 of dolly 100. Pivoting of bell cranks122L, 122R causes handling wheels 120L, 120R to move between thedownward engaged and upward disengaged positions. Left and rightactuators 126L, 126R are connected between frame 101 and left and rightbell cranks 122L, 122R. Actuators 126L, 126R are preferably hydraulicpiston-cylinder rams, which have their cylinder ends pivotally mountedto bracket 125 fixed to the frame 101 at centerline 105 (FIG. 2) andtheir piston ends pivotally connected to arms 124L, 124R on bell cranks122L, 122R, respectively. Lowering handling wheels 120L, 120R (to theposition as shown on the left side of FIG. 5) raises the forward end ofdolly 100 as shown in FIG. 3, so that ODV 8 may be driven into and outof coupling position with respect to dolly 100. To couple dolly 100 toODV 8, handling wheels 120L, 120R are raised (to the position as shownon the right side of FIG. 5) so that sockets 74R, 74L are lowered overballs 72R, 72L, respectively. Once mated, sockets 74R, 74L are locked onto balls 72R, 72L.

FIGS. 6-8 show dolly 100 coupled to ODV 8 by hitches 70R, 70L to form acomplete aircraft transport tractor 10. Once connected, dolly 100 andODV tractor 8 become a single system and operate in harmony to maneuveraircraft lift assembly 200 in position to receive and handle aircraftlanding gear. Because aircraft lift dolly 100 can be quickly and easilycoupled to and uncoupled from ODV 8, ODV 8 can be used with otheraccessories or to perform other tasks, such as moving aircraft withconventional towbars, pulling baggage carts, or plowing snow, forexample. Preferably, appendage ring 9 includes a mount 80 that can beused for other accessories (not shown). Interoperability of ODVs andaccessory tools reduces capital expense and maintenance costs, improvesreliability, and provides operational flexibility, because fewerspecialized tractor vehicles are necessary.

ODV 8 preferably includes a pin 109 that can be selectively engagedbetween ODV frame 14 and appendage ring 9 by the operator. When pin 109is disengaged, appendage ring 9 is freely revolvable about ODV frame 14,and when pin 109 is engaged, appendage ring is held stationary withrespect to ODV frame 14. Locking pin 109 is ideally connected to aflexible control cable that leads to a handle near operators seat 50,making it possible for the operator to conveniently lock the appendagering 9 stationary. In some instances, it may be preferable to lock ring9, such as when ODV 8 is separated from the dolly 100 and is being usedto tow ground equipment with towbars, for example. With appendage ring 9locked, objects may be towed from the front or rear of ODV 8, andprecise movement of the towed object is provided by drive wheels 12R,12L.

In addition to raising the front end of dolly 100 for coupling to anddecoupling from ODV 8, dolly handling assembly 118 may be used to raisedolly wheels 110R, 110L clear of the ground. This is accomplished bylowering handling wheels 120L, 120R while sockets 74R, 74L remain lockedto balls 72R, 72L, as shown in FIGS. 9-10. Because handling wheels 120L,120R are preferably oriented to roll transversely, that is,perpendicularly to longitudinal centerline 105, by pinning rail 9 to ODVframe 14 (with pin 109) so that no relative rotation occurs between thetwo, the entire aircraft transport vehicle 10 can be made to rotateabout vertical axis 16 (as shown by arrow 300) by counter-rotating ODVdrive wheels 12R, 12L. Alternatively, as shown in FIG. 9, if ODV 8 isoriented so that ODV horizontal axis 18 is aligned with dolly centerline105 before rail 9 is pinned to ODV frame 14, aircraft transport vehicle10 can be made to travel transversely in the direction of arrows 302. Inthis manner, aircraft transport vehicle 10 can move aircraft, with theaircraft nose in close proximity to objects such as fences and hangers,yet have a clear access and departure path by moving transversely to theaircraft.

As shown in FIG. 8, dolly wheels 110R, 110L are typically non-steerable.However, in an alternative embodiment of the invention, as shown in FIG.9, dolly wheels 110R, 110L may be mounted on vertical shafts 111R, 111L,respectively, that allow for steering of the wheels. By locking therotating appendage ring 9 of ODV tractor 8 with locking pin 109 andallowing dolly wheels 110R, 110L to either freely swivel or steer inharmony with the chassis movement of ODV tractor 8, the entire aircrafttransport vehicle 10 can be moved in a direction perpendicular tocenterline 105. In this manner, it is possible to move the aircraft in aperpendicular direction from the centerline of fuselage and thereforepivot the aircraft on the rear main landing gear without turning thenose landing gear of the aircraft.

FIG. 11 illustrates another alternative embodiment of the invention, inwhich aircraft lift dolly 100 is longitudinally telescopic toaccommodate aircraft of varying sizes, for example. Telescopic framemembers 130L, 130R allow the front end 102 of dolly 100 to be movedrelative to the rear end 104. One or more pins 132 may be used to locktelescopic frame members 130L, 130R into a given extension position.Alternatively, an actuator 134, such as a hydraulic cylinder-pistonarrangement, may be used to selectively extend or retract the length ofdolly 100. FIG. 11 also illustrates ODV 8 being rotated counterclockwisewith respect to dolly 100 to allow precise positioning of the vehicle10.

Although it is preferable that ODV 8 and dolly 100 are separate,disconnectable components, the invention encompasses an aircrafttransport tractor wherein the ODV 8 is permanently revolvably connectedto the lift dolly 100 to form a specialized vehicle, as shown in FIG.12.

FIGS. 8, 13-14 illustrate the structure of aircraft lift assembly 200according to a preferred embodiment of the invention. The lift assembly200 includes a lift carriage 202 disposed at the rear 104 of dolly 100at centerline 105. Lift carriage 202 is slideably captured betweenguides 203R, 203L, which are in turn mounted to dolly frame 101, so thatcarriage 202 moves up and down vertically but not transversely. Liftcarriage 200 carries one or more horizontally and transversely-orientedrails or shafts 220, 222. The right and left distal ends of shafts 220,222 are slideably captured in vertical slots 205R, 205L of blocks 204R,204L, respectively. Blocks 204R, 204L are in turn mounted to dolly frame101, so that blocks rails 220, 222 move up and down vertically but notlongitudinally. Thus, carriage 202, with rails 220, 222, slide only inthe vertical direction. Other suitable arrangements to slideablyconstrain carriage 202 and rails 220, 222 in the vertical direction maybe used, such as dovetail or T-slot arrangements. Hydraulicpiston-cylinder actuators, 208R, 208L are connected between frame 101and carriage 202 to selectively vertically move carriage 202 and rails220, 222. However, other actuators, such as rack and pinion or leadscrew arrangements for example, may be used in lieu of piston-cylinderactuators.

Two support arms 210R, 210L are slideably carried by rails 220, 222 forlateral movement between positions near centerline 105 to near thedistal ends of lifting rails 220, 222. Linear bearings 211, whichpreferably employ large bearing rollers that roll along each shaft,support lifting arms 210R, 210L. Because rails 220, 222 are cylindrical,two are used to carry arms 210R, 210L so that the arms cannot pivotdownwardly under load. However, a single rail with a splined orrectangular profile, for example, could be used if desired. Hydraulicpiston-cylinder actuators 212R, 212L are connected between lift carriage202 and arms 210R, 210L, respectively, to selectively laterally movearms 210R, 210L. However, other actuator types and arrangements may beused as appropriate.

A forward chock 230 is mounted to the rear wall of lift carriage 202 sothat it is raised and lowered with lift carriage 202. Adjustable rightand left rear chocks 232R, 232L are moveably carried by support arms210R, 210L, respectively. Preferably, each arm 210R, 210L acts as a railupon which its corresponding chock 232R, 232L slides and has a profilethat prevents the chock from pivoting. Rear chocks 232R, 232L are movedlongitudinally along the length of arms 210R, 210L by hydraulicpiston-cylinder actuators 234R, 234L, which are connected between chocks232R, 232L and arms 210R, 210L, respectively. However, other actuatorand chock support arrangements may be used as appropriate.

FIGS. 13-20 illustrate the operational sequence of capturing andelevating an aircraft nose gear 900. As shown in FIGS. 13-14, aircrafttransport vehicle 10 (FIG. 6) is first driven into alignment with nosegear 900 by centering the nose gear 900 with front chock 230 and thenmoved toward the aircraft until front chock 230 abuts the tire(s) ofnose gear 900, as shown in FIG. 15. Referring to FIG. 15, left and rightsupport arms 210L, 210R are then moved toward centerline 105 byactuators 212L, 212R, respectively, until rear chocks 232L, 232R arealigned with the nose gear tire(s), as shown in FIGS. 16-17. Referringto FIG. 16-17, rear chocks 232L, 232R are moved forward by actuators234L, 234R, until the chocks abut the rear of the tires of nose gear900, as shown in FIGS. 18-19. Referring to FIGS. 18-19, hydraulicpressure is applied to lifting rams 208L, 208R whereby carriage 202, andrails 220, 222, arms 210L, 210R, and chocks 230, 232L, 232R carriedthereby, is lifted, thus lifting aircraft nose gear 900 as shown in FIG.20.

Referring to FIG. 13, once carriage 202 is raised by hydraulic rams208R, 208L, a spring-loaded lift lock cam or pin 240 automaticallyengages and locks carriage 202 in the lifted position. A control cable242 is ideally attached to locking cam 240 and leads to console 212,thus allowing the operator to release locking cam 240 from his seat 50for lowering the aircraft back to the ground. Locking cam 240 preventsthe carried aircraft from abruptly falling as a result of hydraulicfailure during handling or transport.

As shown in FIGS. 13-14, limit switches are installed at contact points240 on forward chock 230 and 232R, 234R, 232L, 234L on right and leftrear chocks 232R, 232L, respectively. These limit switches are connectedin series with the electrical circuits that control the motors 26R, 26L(FIG. 2) and hydraulic actuators 212R, 212L, 234R, 234L. The purpose ofthe limit switches is to limit the travel of any of the moving partsshould they come in direct contact with any part of the nose gear 900 ofthe aircraft. In this manner, an operator can be confident that shouldany component be out of the line of site, the limit switches willprevent the lifting arms 210R, 210L or chocks 230, 232R, 232L fromcausing damage to nose gear 900.

Although aircraft lift mechanism 200 as described hereinabove withreference to FIGS. 13-20 is preferably used in conjunction with a liftdolly 100 and/or an ODV 8 tractor, the invention encompasses theaircraft lift mechanism 200 carried by a conventional four-wheeledtractor of prior art. Such a combination provides for faster and safercradling of aircraft than lifts of prior art, because the aircraft neednot be moved for cradling and the operator can perform all requiredfunctions from the operators seat.

While some embodiments of the invention have been illustrated in detail,the invention is not limited to the embodiments shown; modifications andadaptations of the above embodiment may occur to those skilled in theart. Such modifications and adaptations are in the spirit and scope ofthe invention as set forth herein:

1. An aircraft transport dolly (100) comprising: a frame (101) havingfront and rear ends (102, 104) and defining a frame longitudinal axis(105) intersecting said front and rear ends (102, 104); at least onewheel (110R, 110L) rotatively coupled to said frame (101) for supportingat least a portion of the weight of said frame (101); two hitchassemblies (74R, 74L) connected to a front portion of said frame (101)for coupling said frame (101) to a tractor (8) at two points separatelyand equally laterally distant from said frame longitudinal axis; a liftcarriage (202) vertically movably connected to a rear portion of saidframe (101); a lift actuator (208R) coupled between said lift carriage(202) and said frame (101) for selectively raising and lowering theelevation of said lift carriage (202) with respect to said frame (101);a first arm (210R) horizontally movably carried by said lift carriage(202), said first arm (210R) defining a first arm longitudinal axis anddisposed such that said first arm longitudinal axis is substantiallyparallel to said frame longitudinal axis (105), said first arm (210R)moveable substantially transversely to said frame longitudinal axis(105) with respect to said lift carriage (202); a second arm (210L)horizontally movably carried by said lift carriage (202), said secondarm (210L) defining a second arm longitudinal axis and disposed suchthat said second arm longitudinal axis is substantially parallel to saidframe longitudinal axis (105), said second arm (210L) moveablesubstantially transversely to said frame longitudinal axis (105) withrespect to said lift carriage (202); a first chock (230) carried by saidlift carriage (202); and a second chock (232R) movably carried by saidfirst arm (210R); and a third chock (232L) movably carried by saidsecond arm (210L); whereby said first chock (230) may be disposed on oneside of an aircraft nose gear (900) and said second and third chocks(232R, 232L) may be selectively disposed on the opposite side of saidaircraft nose gear (900) to cradle said aircraft nose gear (900) betweensaid first chock (230) and said second and third chocks (232R, 232L),and said lift carriage (202) may be raised, elevating said first, secondand third chocks (230, 232R, 232L) and said nose gear (900).
 2. Thedolly (100) of claim 1 wherein: said second chock (232R) moveable in adirection substantially parallel to said frame longitudinal axis (105)with respect to said first arm (210R); and said third chock (232L)moveable in a direction substantially parallel to said framelongitudinal axis (105) with respect to said second arm (210L).
 3. Thedolly (100) of claim 1 further comprising: a first arm actuator (212R)coupled between said first arm (210R) and said lift carriage (202) forselectively moving said first arm (210R) with respect to said liftcarriage (202); a first chock actuator (234R) coupled between saidsecond chock (232R) and said first arm (210R) for selectively movingsaid second chock (232R); a horizontally-oriented rail (220) carried bysaid lift carriage (202), said first arm (210R) and said second arm(210L) supported by said rail (220); a second arm actuator (212L)coupled between said second arm (210L) and said lift carriage (202) forselectively moving said second arm (210L) with respect to said liftcarriage (202); a second chock actuator (234L) coupled between saidthird chock (232L) and said second arm (210L) for selectively movingsaid third chock (234L).
 4. The dolly (100) of claim 1 wherein: saidframe (101) includes a rail (130R) oriented longitudinally with respectto said frame longitudinal axis (105) and disposed between said frontend (102) and said rear end (104), said rear end (104) selectivelylongitudinally telescopically movable with respect to said front end(102) along said rail (130R).
 5. The dolly (100) of claim 1 wherein:each said hitch assembly (74R) is arranged to uncouple said dolly (100)from said tractor (8) when said front portion of said frame (101) iselevated with respect to said tractor (8); and said dolly (100) furtherincludes a dolly handling mechanism (118) coupled to said front portionof said frame (101) and arranged to lift said front portion of saidframe (101) for uncoupling said dolly (100) from said tractor (8). 6.The dolly (100) of claim 5 wherein: aid dolly handling mechanism (118)includes a handling wheel (120R) oriented perpendicularly to said framelongitudinal axis (105), whereby said handling wheel (120R) can belowered with respect to said frame (101) to raise said at least onewheel (110R, 110L) to allow said dolly (100) to be moved in a directionperpendicular to said frame longitudinal axis (105).
 7. An aircrafttransport vehicle (10) comprising: a frame (101) having front and rearends (102, 104) and defining a frame longitudinal axis (105)intersecting said front and rear ends (102, 104); two hitch assemblies(74R, 74L) connected to said front end of said frame (101) for couplingsaid frame (101) to a tractor section (8) at two points separately andequally laterally distant from said frame longitudinal axis; a pluralityof wheels (110R, 110L, 12R, 12L) rotatively coupled to said frame (101)for supporting the weight of the vehicle (10); a lift carriage (202)vertically movably connected to a rear portion of said frame (101); alift actuator (208R) coupled between said lift carriage (202) and saidframe (101) for selectively raising and lowering the elevation of saidlift carriage (202) with respect to said frame (101); a first arm (210R)horizontally movably carried by said lift carriage (202); said first arm(210R) defining a first arm longitudinal axis and disposed such thatsaid first arm longitudinal axis is substantially parallel to said framelongitudinal axis (105), said first arm (210R) moveable substantiallytransversely to said frame longitudinal axis (105) with respect to saidlift carriage (202); a second arm (210L) horizontally movably carried bysaid lift carriage (202), said second arm (210L) defining a second armlongitudinal axis and disposed such that said second arm longitudinalaxis is substantially parallel to said frame longitudinal axis (105),said second arm (210L) moveable substantially transversely to said framelongitudinal axis (105) with respect to said lift carriage (202); afirst chock (230) carried by said lift carriage (202); and a secondchock (232R) movably carried by said first arm (210R); and a third chock(232L) movably carried by said second arm (210L); whereby said firstchock (230) may be disposed on one side of an aircraft nose gear (900)and said second and third chocks (232R, 232L) may be selectivelydisposed on the opposite side of said aircraft nose gear (900) and saidlift carriage (202) may be raised, elevating said first and secondchocks (230, 232R) and said nose gear (900).
 8. The vehicle (10) ofclaim 7 wherein: said second (232R) moveable in a directionsubstantially parallel to said frame longitudinal axis (105) withrespect to said first arm (210R); and said third chock (232L) moveablein a direction substantially parallel to said frame longitudinal axis(105) with respect to said second arm (210L).
 9. The vehicle (10) ofclaim 7 further comprising: a first arm actuator (212R) coupled betweensaid first arm (210R) and said lift carriage (202) for selectivelymoving said first arm (210R) with respect to said lift carriage (202); afirst chock actuator (234R) coupled between said second chock (232R) andsaid first arm (210R) for selectively moving said second chock (232R); ahorizontally-oriented rail (220) carried by said lift carriage (202),said first arm (210R) and said second arm (210L) carried by said rail(220); a second arm actuator (212L) coupled between said second arm(210L) and said lift carriage (202) for selectively moving said secondarm (210L) with respect to said lift carriage (202); and a second chockactuator (234L) coupled between said third chock (232L) and said secondarm (210L) for selectively moving said third chock (232L).
 10. Thevehicle (10) of claim 7 wherein: said frame (101) includes a rail (130R)oriented longitudinally with respect to said frame longitudinal axis(105) and disposed between said front end (102) and said rear end (104),said rear end (104) selectively longitudinally telescopically movablewith respect to said front end (102) along said rail (130R).
 11. Thevehicle (10) of claim 7 wherein: first and second of said plurality ofwheels (12R, 12L) are independently powered drive wheels disposed abouta common horizontal axis (18) that bisects a vertical axis (16), saidfirst and second of said plurality of wheels (12R, 12L) arranged torevolve 360 degrees about said vertical axis (16) with respect to saidlift carriage (202).
 12. The vehicle of (10) claim 7 wherein: a frontportion of said vehicle (10) is selectively disconnectable from saidrear portion; and said front portion defines a tractor (8).
 13. In aservice vehicle (10) including an omni-directional vehicle (8)characterized by having first and second independently powered drivewheels (12R, 12L) rotatably disposed along a horizontal axis (18) anddesigned and arranged to revolve 360 degrees about a central verticalaxis (16) which intersects said horizontal axis (18) between said firstand second drive wheels (12R, 12L), the improvement comprising: anaircraft transport dolly (100) having a frame (101), a front end (102)revolvably connected to said omni-directional vehicle (8), and a rearend (104) having and least one dolly wheel (110R, 110L), said front endand said rear end defining a frame longitudinal axis (105) intersectingsaid front and rear ends (102, 104), and carrying an aircraft liftmechanism (200) designed and arranged for receiving a nose gear (900) ofan aircraft and selectively elevating said nose gear (900) with respectto said service vehicle (10), said dolly (100) defining a framelongitudinal axis (105) intersecting said front and rear ends (102,104), two hitch assemblies (74R, 74L) connected to said front portion ofsaid frame (101) for coupling said frame (101) to said omni-directionalvehicle (8) at two points separately and equally laterally distant fromsaid longitudinal axis (105); said aircraft lift mechanism having a liftcarriage and having a first arm horizontally movably carried by saidlift carriage, said first arm (210R) defining a first arm longitudinalaxis and disposed such that said first arm longitudinal axis issubstantially parallel to said frame longitudinal axis (105), said firstarm (210R) moveable substantially transversely to said framelongitudinal axis (105) with respect to said lift carriage (202), and asecond arm (210L) horizontally movably carried by said lift carriage(202), said second arm (210L) defining a second arm longitudinal axisand disposed such that said second arm longitudinal axis issubstantially parallel to said frame longitudinal axis (105), saidsecond arm (210L) moveable substantially transversely to said framelongitudinal axis (105) with respect to said lift carriage (202). 14.The vehicle (10) of claim 13 further comprising: a ring (9) encirclingsaid omni-directional vehicle (8) and revolvably coupled thereto by aplurality of engaging elements (44, 46, 47) generally circuminterspersedtherebetween, said dolly (100) connected to said ring (9); whereby thegenerally circuminterspersed position between said omni-directionalvehicle (8) and said ring (9) of said plurality of engaging elements(44, 46, 47) provides a loading that is generally evenly distributedabout the perimeter of said omni-directional vehicle so that said dolly(100) revolves freely with respect to said omni-directional vehicle (8).15. The vehicle (10) of claim 13 wherein: said frame (101) includes atleast one wheel (110R, 110L) rotatively coupled to said frame (101) forsupporting at least a portion of the weight of the frame (101); saidlift carriage (202) vertically movably connected to a rear portion ofsaid frame (101) and includes, a first arm actuator (212R) coupledbetween said first arm (210R) and said lift carriage (202) forselectively moving said first arm (210R) with respect to said liftcarriage (202), a first chock (230) carried by said lift carriage (202),a second chock (232R) movably carried by said first arm (210R), and afirst chock actuator (234R) coupled between said second chock (232R) andsaid first arm (210R) for selectively moving said second chock (232R), asecond arm actuator (212L) coupled between said second arm (210L) andsaid lift carriage (202) for selectively moving said first arm (210R andsaid second arm respect to said lift carriage (202), a third chock(232L) movably carried by said second arm (210L), a first chock actuator(234R) coupled between said second chock (232R) and said first arm(210R) for selectively moving said second chock (232R), a second chockactuator (234L) coupled between said third chock (232L) and said secondarm (210L) for selectively moving said third chock (232L); said firstarm (210R) defines a first arm longitudinal axis and is disposed suchthat said first arm longitudinal axis is substantially parallel to saidframe longitudinal axis (105); said first arm (210R) is arranged to movesubstantially transversely to said frame longitudinal axis (105) withrespect to said lift carriage (202); and said second chock (232R) isarranged to move in a direction substantially parallel to said framelongitudinal axis (105) with respect to said first arm (210R); saidsecond arm (210L) defines a second arm longitudinal axis and is disposedsuch that said second arm longitudinal axis is substantially parallel tosaid frame longitudinal axis (105); said second arm (210L) is arrangedto move substantially transversely to said frame longitudinal axis (105)with respect to said lift carriage (202); and said third chock (232L) isarranged to move in a direction substantially parallel to said framelongitudinal axis (105) with respect to said second arm (210R); wherebysaid first chock (230) may be disposed on one side of an aircraft nosegear (900) and said second and third chocks (232R, 232L)) may bedisposed on the opposite side of said aircraft nose gear (900) and saidlift carriage (202) may be raised, elevating said first, second, andthird chocks (230, 232R, 232L) and said nose gear (900).
 16. The vehicle(10) of claim 15 further comprising: a horizontally-oriented rail (220)carried by said lift carriage (202), said first arm (210R) carried bysaid rail (220); a second chock actuator (234L) coupled between saidthird chock (232L) and said second arm (210L) for selectively movingsaid third chock (232L).
 17. The vehicle (10) of claim 13 wherein: saidframe (101) includes a rail (130R) oriented longitudinally with respectto said frame longitudinal axis (105) and disposed between said frontend (102) and said rear end (104), said rear end (104) selectivelylongitudinally telescopically movable with respect to said front end(102) along said rail (130R).
 18. The vehicle (10) of claim 13 wherein:said hitch assembly (70R, 72R, 74R) is arranged to uncouple said dolly(100) from said omni-directional vehicle (8) when a front portion ofsaid frame (101) is elevated with respect to said omni-directionalvehicle (8); said dolly (100) further includes a dolly handlingmechanism (118) coupled to said front portion of said frame (101) andarranged to lift said front portion of said frame (101) for uncouplingsaid dolly (100) from said tractor (8) or to lift said at least onedolly wheel (110R, 110L) clear of the ground; and said dolly handlingmechanism includes a handling wheel (120R) oriented perpendicularly tosaid frame longitudinal axis (105).
 19. In a service vehicle (10)including an omni-directional vehicle (8) characterized by having afirst and second independently powered drive wheels (12R, 12L) rotatablydisposed along a horizontal axis (18) and designed and arranged torevolve 360 degrees about a central vertical axis (16) which intersectssaid horizontal axis (18) between said first and second drive wheels(12R, 12L), the improvement comprising: a hitch coupled to saidomni-directional vehicle, and an aircraft transport dolly (100) having aframe (101), a front end (102) slideably connected to said hitch, and arear end (104), said front end (102) and said rear end (14)) defining aframe longitudinal axis (105) intersecting said front and rear ends(102, 104), having at least one dolly wheel (110R, 110L) and carrying anaircraft lift mechanism (200) designed and arranged for moving the nosegear of an aircraft vertically for transporting said aircraft saidaircraft lift mechanism having a lift carriage and having a first armhorizontally movably carried by said lift carriage, at least one hitchassembly (74R, 74L) at said front end of said frame (101) for couplingsaid frame (101) to said omni-directional vehicle (8) and fixedlycontacting said omni-directional vehicle at two points separately andequally laterally distant from said longitudinal axis (105); said firstarm (210R) defining a first arm longitudinal axis and disposed such thatsaid first arm longitudinal axis is substantially parallel to said framelongitudinal axis (105), said first arm (210R) moveable substantiallytransversely to said frame longitudinal axis (105) with respect to saidlift carriage (202); and a second arm (210L) movably carried by saidlift carriage (202), said second arm (210L) defining a second armlongitudinal axis and disposed such that said second arm longitudinalaxis is substantially parallel to said frame longitudinal axis (105),said second arm (210L) moveable substantially transversely to said framelongitudinal axis (105) with respect to said lift carriage (202).